testing of additive manufactured corrosion- resistant alloys ... - dnv gl am materials...nace tm0177...

DNV GL © 16 October 2018 SAFER, SMARTER, GREENERDNV GL ©

16 October 2018

Testing of Additive Manufactured Corrosion-Resistant Alloys for Oil and Gas Industry

1

Liu Cao, Bill Kovacs, Ramgo Thodla

Christopher Taylor

Materials Technology Development Section, Dublin, OH

DNV GL © 16 October 2018

Additive Manufacture (AM)

2

AM or 3D Printing builds three-dimensional solid objects successively layer-by-

layer from digital models.

ASTM F2792

AM Processes

Directed

Energy

Deposition

Powder

Bed Fusion

Materials

Extrusion

Materials

Jetting

Binder

Jetting

Sheet

Lamination

Vat

Photopoly-

merization

Mate

rials

plastic ✔ ✔ ✔ ✔ ✔ ✔

metal ✔ ✔ ✔ ✔

ceramic ✔ ✔

composite ✔ ✔ ✔

otherswax,

photopolymersand paper

resin, liquid

photopolymer

Energy SourceLaser, electron

beam

Laser, electron

or ion beamheating coil

heating coil, UV

lightN/A

Laser,

ultrasonic

UV light, X-

ray or γ-rays

Relevant Terms

LENS, DMD,

LBMD, EBF3,

DLF, LFF, LC,

CMB, IFF

SLS, SLM,

DMLS, DMP,

EBM, SPS,

Laser Cusing

FDM,

FFF,

FLM

Inkjet, PolyJet,

MJM, Aerosol

Jet, ThermoJet

3DP,

LPS,

DSPC

LOM,

UC,

UAM

SL, SLA,

MPSL,

DLP, FTI

Part Durability

Detail Precision

Surface Roughness

Build Speed Slow Slow Medium Medium Fast Fast Medium

Cost High High Low Low Medium Medium Medium

Support No Yes Yes Yes No No Yes

Post-process Yes Yes Minimum Minimum Yes Yes No

High Durability Low

High Surface Roughness Low

Low Detail or Precision High


Benefits & Challenges of AM for O&G Industry

▪ Complexity for free

– Better strength weight ratio

– Fewer components

– Internal channels/lattice

▪ Fast production run

– Ideal for highly customized & low

volume product

▪ Near net shape manufacturing

– Save materials & machining

– Precious metal, high strength

alloys, ceramics

▪ Distributed production

– Simple supply chain

– Low inventory

3

Design for build, support structure

Integrity/quality of complex component

Surface finish to remove inferior “skin”

For critical component, mandatory

qualification and/or certification

through the entire AM production chain

Quality control

Safety & reliability

Expensive machine & powder material

Post-fabrication treatment/finish

Trade-off


Major Issues Related to AM in Oil & Gas

▪ Inherently anisotropic properties and intrinsic defects.

▪ Variability within and between samples or build batches.

▪ Post processing is necessary (HIP-hot isostatic pressing, annealing, heat

treatment, surface finish)

– Post processing may also create problems

▪ Proprietary processes not transparent to end-user

▪ AM is not a production route addressed by existing standard, i.e. NACE

MR0175 / ISO 15156-2015.

▪ Do you qualify it as a product or a process or both?

▪ Uncertainties in reliability and material degradation in a long run.

4


Corrosion Testing of AM CRAs for Oil & Gas

1. 2017 – mechanical, electrochemical and sour testing of AM 17-4PH

stainless steel

2. 2018 – mechanical, electrochemical and sour testing of AM 17-4PH

stainless steel with improved heat treatment

3. 2019 – Susceptibility to hydrogen embrittlement of AM 718 nickel-

based alloy with API 6ACRA specified heat treatment

5

Case Studies

W. Kovacs et al, CORROSION/18, paper no. 11212, (Phoenix, AZ: NACE, 2018)

W. Kovacs et al, CORROSION/17, paper no. 9667, (New Orleans, LA: NACE, 2017)

L. Cao et al, CORROSION/19, paper no. 9472, (Houston, TX: NACE, 2019),

submitted


2017 Testing of AM 17-4PH

▪ 17-4PH (UNS S17400) stainless steel from

multiple production routes, heat-treated to

H1150D*

– Wrought (Rod and Plate, H1150D)

– Welded (Plate cut, grooved & GMAW, H1150D

heat treated post welding)

– AM (DMLS + HIP + H1150D) – argon cover gas,

10 ≤ powder size ≤ 55 µm

▪ Testing:

– Mechanical Properties

– Chemistry

– Metallography

– Corrosion tests (CPP, NACE TM0177 Method A)

* NACE heat treatment in old reference.



7

Macrohardness

Triplicate HRC on each

specimen (different XZ /

YZ planes for AM).

– Poor repeatability on

some AM samples

(and 1 weld)

– 1 AM sample below

minimum spec for

H1150D (24 HRC)

– AM samples on low

end of allowed

hardness range (24-

33 HRC)



8

Mechanical Properties

▪ All YS ≥ 105 ksi min

▪ AM material have

higher yield, lower

hardness, elongation,

ROA (measured Z-axis

direction only – should

show worst

properties)

▪ AM material has

highest YS/TS ratio,

≤85% desirable as

indicator of austenite

fraction and proper

aging for sour service.



9

Metallography

a) Rod 3 – 400X (orig. mag.)

10% ammonium persulfate electrolytic etchant b) AM 1-XY-plane – 400X (orig. mag.)

Ralph’s reagent

c) AM 1-XZ plane – 400X (orig. mag.)

Ralph’s reagent d) AM 1-YZ-plane – 400X (orig. mag.)

Ralph’s reagent

50 µm 50 µm

50 µm 50 µm

▪ Chemistry meet

MR0175

specification

▪ Similar grain size

▪ Larger martensite

lath spacing AM

material

▪ More inclusions and

porosity on AM

parts Z-planes (red

circles)



10

Microhardness

▪ Vickers HV 0.1

(100 g) used to

make small

indents (but

larger than 22

µm)

▪ Hardness: AM

XZ > AM XY >

Rod

▪ Some individual

readings above

328 Hv (with HV

0.1)



11

Cyclic Potentiodynamic Polarization

OCP for 2 hours,

iApex = 1 mA/cm2, 0.167 mV/s

-100 mVOCP to -100 mVOCP

1E-11 1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

Po

tentia

l (V

vs.

SH

E)

Current Density (A/cm2)

wrought

AM xy-plane

AM z-axis

17-4PH samples

deaerated 1 M NaCl

room temperature

(a) Wrought (b) AM xy-plane (c) AM z-axis

Figure 4: Images of post-test sample surfaces.

Z

▪ AM-XY similar to wrought – positive hysteresis (localized corrosion), crevice

under gasket

▪ AM-XZ inferior – higher current density, less passive, pitting without crevice

– Passive current density is about 10x of wrought/ AM XY plane

– Expecting galvanic corrosion with itself or wrought material of same grade



12

NACE TM0177 Method A Uniaxial Tensile Testing

▪ SSC testing in two conditions (both above the MR0175 recommended limit), 90-100% AYS:

– High = 105 psi H2S, 105 psi CO2, pH 3.5, 100 ppm Cl-, 21±3 °C

– Low = 15 psi H2S, pH 3.5, 100 ppm Cl-, 21±3 °C

▪ In both env., wrought/welded survived 30 days, AM failed in



13

NACE TM0177 Method A for SSC Susceptibility

10X (orig. mag.).

▪ High H2S condition:

o Multiple “dark”

crack initiation sites in edge of

“bright” cracking

regions on each AM specimen

o Presence of secondary cracks

▪ Low H2S condition:


Conclusions of 2017 Testing

▪ AM parts are worse than wrought and welded counterparts by:

– variability in (macro) hardness

– higher YS/TS ratio

– lower ductility in the Z-direction

– local (micro) hardness greater than wrought material

– reduced resistance to localized corrosion when the Z-plane is

exposed.

– greatly reduced sour service performance

▪ Likeliest cause of poorer performance are inhomogeneities

(inclusions, precipitates) and scale/defects (intra-layer defects,

porosity) resulting from the feedstock, fabrication and/or heat

treatment.


2018 Testing of 17-4PH

▪ Test properties and sour performance of 17-4PH (UNS

S17400) Grade 630 H1150D from two build orientations

▪ Trends between standard qualification methods and sour

performance, rapid screening method

▪ Materials:

– 2018 AM (DMLS + HIP + H1150D), Ar/Ar

(atomization/build cover gas), 10 ≤ size ≤ 55 µm

– Z-axis & X-axis build direction, no homogenization

treatment

– Different heat treatment

▪ Testing:

– Chemistry, Mechanical Properties, Hardness,

Metallography

– Corrosion tests (LPR, CPP, NACE TM0177 Method A)



16

Macrohardness

▪ Five HRC on each

specimen (XY face of

Z-build, XZ face of X-

build, and XY face of X-

build).

▪ Select “best” and

“worst” sample from

each orientation for

electrochemistry.

▪ Little difference

between test faces of

same blank

▪ Improved repeatability

vs. 2017 AM blanks.



17

Mechanical Properties

▪ All ≥ 724 Mpa / 105

ksi min

▪ Minimal Difference

between Z-Build and

X-Build

▪ Some strength has

been sacrificed in

heat treatment in

order to achieve

reduced YS/TS ratio

and improved

elongation and ROA

▪ 2018 materials YS/TS

ratio ≤85%



18

Metallography

Z-build X-build

▪ Powder chemistry meet NACE specification, higher Creq and lower Nieq hasten

martensite formation, expected to result in poorer sour performance

▪ 1 μm polish followed by Fry’s reagent and 500X imaging

▪ Similar grain size and microstructure with differing orientations

▪ Typical “wrought” microstructure



19

Electrochemical Testing

▪ “Best” and “worst” from hardness repeatability from each build orientation (Z-Build and X-Build)

▪ As-fabricated surface and polished with 800 grit

▪ Masking used to prevent crevices observed in 2017 work

▪ OCP and LPR every 15 minutes for 4 hours, then CPP using 3-electrode (SCE reference) flat cell – 1M NaCl deaerated at 20 °C.

▪ CPP scan from -50 mV at 0.167 mV/s to 1 mA/cm2 reverse apex current density back to -50 mV vs. OCP

N2



20

OCP Measurements

0 1 2 3 4-300

-200

-100

0

100

200

0 1 2 3 4-300

-200

-100

0

100

200

X-Build

as-fab, worst, xz-plane polished, worst, xz-plane

as-fab, worst, xy-plane polished, worst, xy-plane

as-fab, best, xz-plane polished, best, xz-plane

as-fab, best, xy-plane polished, best, xy-plane

Co

rro

sio

n P

ote

ntia

l (m

V v

s. S

HE

)

Time (hour)

xz-plane, 2017

xy-plane, 2017

Z-Build

Time (hour)

0 1 2 3 4

0.01

0.1

1

0 1 2 3 4

0.01

0.1

1

X-Build

as-fab, worst, xz-plane polished, worst, xz-plane

as-fab, worst, xy-plane polished, worst, xy-plane

as-fab, best, xz-plane polished, best, xz-plane

as-fab, best, xy-plane polished, best, xy-plane

Corr

osio

n R

ate

(

A/c

m2)

Time (hour)

Z-Build

zx- or xy-plane, 2017

Time (hour)

LPR CR Measurements

▪ As-fab surfaces have more scatter, lower OCP (~200 mV) and higher corrosion rate

▪ On polished surfaces

– “Worst” hardness have lower OCP and higher corrosion rate

– XZ-plane has up to 30-50 mV lower OCP than XY-plane

– X-Build specimens have lower OCP (50-100 mV) and higher corrosion rate than Z-Build

specimens for same surface orientation



21

Cyclic Potentiodynamic Polarization: Surface Finish

1E-121E-111E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

AM 17-4PH, xz-plane,

deaerated 1 M NaCl,

room temperature

Po

tentia

l (V

vs.

SH

E)


as-fabricated

polished

1E-121E-111E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Po

tentia

l (V

vs.

SH

E)


as-fabricated

polished

AM 17-4PH, xy-plane,

deaerated 1 M NaCl,

room temperature

▪ As-fabricated did not show typical passive region

▪ As-fabricated surfaces have 150-200 mV lower OCP and ≥ 300 mV lower pitting potential

▪ As-fabricated surface is inferior to polished surface with ~1.5 mm “skin”

depth removed. AM as-fabricated surfaces may be more detrimental to corrosion behavior than the bulk composition/microstructure



22


Polished Z-build, XY-plane (build direction out of page)

As-fabricated

▪ Small pitting only on as-fabricated surfaces, vs. significant pitting and crevice attack on polished surface.

▪ Other defects seen on as-polished surfaces indicate higher porosity of 2018 AM vs. 2017 AM (similar features not observed).



23


▪ Selective attack on polished specimens gives feather appearance (see SEM

at 50-5000X)

▪ EDS on remaining material shows elevated C, Nb and Cr and decreased

levels of Ni – austenite may be preferentially attacked



24

Cyclic Potentiodynamic Polarization: 2017 vs. 2018

▪ Corrosion potential

improved in 2018 by

150 mV on XY plane

and 300 mV on Z-plane

▪ Breakdown potential

improved; suppression

of crevice could be

largely responsible for

this behavior

▪ Growth of localized

corrosion was similar for

both batches of AM

specimens1E-121E-111E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

worst hardness

2017

Po

ten

tial (V

vs. S

HE

)


wrought

AM xy-plane

AM z-plane

17-4PH

z-build AM samples

deaerated 1 M NaCl

room temperature

2018

best hardness



25

Cyclic Potentiodynamic Polarization: Build and Orientation

▪ Z-plane or XY-plane of Z-Build specimen has subtly higher OCP and

fewer meta-stable events than X-Build specimens

▪ Could be related to fusion area difference and/or potentially energy

density differences because of incident angle changes.

1E-11 1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

AM 17-4PH,

polished xz-plane,

deaerated 1 M NaCl,

room temperature

Po

tentia

l (V

vs.

SH

E)


z-build

xy-build

1E-11 1E-10 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0.01 0.1-0.2

-0.1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

AM 17-4PH,

polished xy-plane,

deaerated 1 M NaCl,

room temperature

Po

tentia

l (V

vs.

SH

E)


z-build

xy-build



26

▪ SSC testing in two conditions (both at the MR0175 recommended limit),

90% AYS:

– A = 0.5 psi H2S, 14 psi CO2, pH 4.5, 100 ppm Cl-, 21±3 °C

– B = 0.5 psi H2S, 14 psi CO2, pH 4.5, 25 ppm Cl-, 21±3 °C

▪ In both env., some specimens survived (one with subcritical flaws) and three

failed specimens had evidence of single initiation.


10X (orig. mag.)

Single discoloredinitiation site



27


Results Year

Orientation

ppH2S, psi

pH[Cl-], mg/L

Applied Stress,

MPa

Hardness, HRC

YS/TS

Ratio

TTF –Avg. ±

1σ, hours

Result

2017 Z-Build105

3.5 100 82924.6 0.93 ≤ 24 3/3 cracked

15 28.3 0.93 ≤ 24 3/3 cracked

2018

X-Build

0.5 4.5

100 (Env.

A)

683 28.9 0.80416 ±221

1/3 pass2/3 cracked

Z-Build 689 28.4 0.82708 ±

171/3 pass

2/3 cracked

X-Build 25 (Env.

B)

683 28.9 0.80629 ±112

1/3 pass2/3 cracked

Z-Build 689 28.4 0.82540 ±142

3/3 cracked

Triplicate AM UNS S17400 H1150D at 22°C (72°F), 90% AYS



28

Scanning Electron Microscopy: CPP vs. NACE Method A

Selective attack on specimen surface is likely initiator of failure in

both CPP and NACE Method A testing.

Fracture Face Overview at 10X (orig. mag.). Image/Location 3-5 at 150X (orig. mag.).

Image/Location 3-5 at 500X (orig. mag.). Image/Location 3-5 at 2500X (orig. mag.).

2017 AM 1 (Z-Build) – SSC Test in

Low H2S, dark site on edge

2018 AM (Z-Build, XY-Plane)

– CPP Test in 1 M NaCl


Conclusions of 2018 Testing

29

▪ Small alterations to post-HIP heat treatments had large benefit in performance,

overcoming even inferior powder composition and higher porosity of 2018 AM

vs. 2017 AM.

– Translated to improved corrosion resistance of 2018 AM parts

▪ The 2018 Z-Build and X-Build (both with low YS/TS ratios) can outperform

wrought and welded counterparts with higher YS/TS ratios.

▪ As-fabricated surface had great data scatter, lower corrosion resistance

compared to polished surfaces with 1.5 mm “skin” removed.

▪ Specimens with the best hardness consistency exhibit slightly improved

corrosion resistance.

▪ Similar corrosion resistance seen on XY-plane or Z-plane, although the XY plane

is typically slightly better.

▪ Electrochemical results indicates slightly better corrosion resistance of Z-Build

specimens than X-Build specimens. Inconclusive in NACE Method A testing.

▪ Hardness and electrochemical measurements (OCP and LPR) can be used as

rapid screen methods.


2019 Testing of AM 718

▪ Susceptibility of hydrogen embrittlement (HE) Inconel 718 (UNS

N07718) from two build orientations

▪ Effects of STA on HE of AM 718 with indication of microstructure and

performance, in comparison to wrought 718

▪ Materials:

– AM 718 (PBF + stress relief + HIP + STA per API 6ACRA 140 ksi

designation)

– Z-axis (vertical) & X-axis (horizontal) build directions

▪ Testing:

– Slow strain rate (SSR) tensile test in deaerated 3.5% NaCl under

cathodic protection (CP)

– Static crack growth rate (SCGR) test in deaerated 3.5% NaCl (pH 8.2)

under a variety of applied CP potentials

– Microstructure characterization by SEM, TEM, EBSD



31

Horizontal

Vertical

CT specimen

SSR/tensile specimen

AND



MaterialDNV GL

ID

Solution Annealing

(Temp./Time/Quench medium)

Age Hardening

(Temp./Time/Quench medium)

AM 718 (140 ksi) 2988 1052°C(1) / 1.5h / Water 760°C(2) / 6h / Air

Wrought 718 (120 ksi) 2276 1030°C / 1.5h / Water 780°C / 7h / Air

Wrought 718 (140 ksi) 2625 1030°C / 1.6h / Water 780°C / 6.5h / Air

32

Solution Treatment and Ageing (STA)

Rationale of STA for AM 718: maximum allowable solution treatment temperature (not

exceed 1052°C) per API 6ACRA to promote redissolution of ’, ’’ and δ-phase; and as low

as possible ageing temperature (760°C) to minimize δ-phase formation or other

deleterious phases (e.g., Laves).

(wt%) Al Si Ti Cr Mn Fe Co Ni Nb Mo Ta

AM 718 (2988) 0.80 0.38 1.08 19.03 0.60 18.26 0.63 50.60 4.77 3.05 1.5

Wrought 718

120ksi (2276)*0.44 - 0.98 18.4 0.10 18.72 0.21 53.0 4.92 2.89 -

Wrought 718

140ksi (2276)*0.48 - 0.94 18.35 0.11 17.94 0.42 53.5 5.01 3.05 -

Chemical Composition



33

SSR Test Results

AM 718, vertical

AM 718, horizontal

1 day precharging



34

▪ SSR test results of AM 718 under cathodic protection is comparable for

wrought counterparts

Materials ConditionMax

Load, lbUTS, ksi tf, h Total %El %εp %RA

AM 718 (140

ksi), vertical3.5% NaCl + CP 3288 185 122.6 21.9% 16.6% 25.0%

AM 718 (140

ksi), horizontal3.5% NaCl + CP 3262 185 108.6 19.4% 13.7% 22.9%

Wrought 718

(140 ksi)*

Air 3141 178 180.0 32.4% 26.2% 39.2%

3.5% NaCl + CP 2976±5 168±0.3 125.9±0.6 22.7%±0.1 12.5%±3.6 16.0%±4.9

Wrought 718

(120 ksi)*

Air 3191 180 181.2 32.6% 26.0% -

3.5% NaCl + CP 2962±36 167±4 98±18.4 18.1%±3.9 16.6%±0.1 -



35

AM

718,

vert

ical

AM

718,

horizonta

l

Miro-void ductile Intergranular Transgranular w/ slip steps



36

▪ Similar fracture features previously found on wrought 718 140 ksi samples

Grain boundary δ phase precipitate

Miro-void ductile Intergranular Transgranular w/ slip steps



37

SCGR Test Procedure

Kmax (ksi in) Kmin (ksi in) f (Hz) da/dt (mm/s) Da (mm) Comments90 54 0.100000099 4.64E-05 0.00868822 'Beff=0.4344"'

90 54 0.01000001 9.43E-06 0.00382109 '90/10'

90 54 0.000999999 5.44E-06 0.00518067 '900/100'

90 54 0.0001 1.26E-05 0.018705751 '9000s holds'

90 Constant K 1.04E-05 0.008749034 'constant Kmax'

90 Constant K 5.91E-06 0.002072606 'Eapp =-1150mV vs SCE'

90 Constant K 3.45E-06 2.82E-03 'Eapp=-1100mV vs SCE'

90 Constant K 1.88E-06 0.002963693 'Eapp=-1050mV vs SCE'

90 Constant K 6.85E-07 0.002260698 'Eapp=-1000mV vs SCE'

90 Constant K 2.66E-07 1.97E-03 'Eapp=-950mV vs SCE'

90 Constant K 7.37E-08 0.002070495 'Change to -900mV SCE'

90 Constant K 3.67E-09 0.000445623 'Eapp to -850 mV vs SCE'

90 Constant K 1.14E-05 0.005623467 'Eap to -1200mV vs SCE'

90 Constant K 6.50E-06 0.001860668 'Eapp to -1150mV vs SCE'



90 Constant K 1.27E-06 0.008519321 'Eapp to -1000 mV vs SCE'



90 Constant K 1.39E-07 2.42E-03 'Eapp to -900mVvs SCE'


thold

K max

Time

K

K min , R = 0.5

1h 2.5h 24h

Constan t at

K max

▪ FCGR to SCGR Transition ▪ pH 8.2 maintained by circulating 3.5% NaCl and adding HCl

▪ Parameters used in transition and SCGR Test

thold



38

Preliminary SCGR Results ▪ Crack length was monitored by direct current potential

drop (DCPD) method. Voltage

drop was converted to crack

length using Johnson

equation in ASTM E1457.

▪ 2~5 times higher CGR of AM

718 in same environment

under CP (


Conclusions of 2019 AM 718 Testing

▪ Post-fabrication heat treatment (referred to STA process) is equally important for

AM 718 parts to gain higher strength and tune microstructure to meet

performance requirements.

▪ In SSR test, heat-treated AM 718 vertical and horizontal specimens exhibited

similar performance which are comparable to wrought 718.

▪ The fracture surface morphology of AM 718 and wrought 718 SSR specimens was

similar: mixed intergranular and transgranular. The intergranular fracture is

related to the presence of intergranular δ-phase and transgranular surface is

roughed with slip steps.

▪ In SCGR test, AM 718 horizontal specimen showed the same trend found on

wrought 718: crack growth rate increased by decreasing the applied potential

(more negative). However, the magnitude of crack growth rate was 2~5 times

higher than the wrought counterpart at each applied potential except -850 mVSCE,

where hydrogen generation is a rate limiting step.

39


Summary on AM Work

▪ Columbus lab is active in several AM qualification and fit-for-purpose testing

projects focused on oil and gas upstream industry, Navy and power generation

▪ Developing an understanding of materials is key to successful insertion of AM

parts in critical service

– Proprietary processes is a challenge in understanding processing

– Rapid changes in technology means properties are changing

▪ Post-fabrication heat treatment, i.e. stress relieve, HIP, STA, is critical to control

properties of final AM metal parts, which can be on a par with wrought

counterparts or excel.

▪ Think out of box: tailor traditional metal development for AM

– As results of fast solidification, AM is capable to produce microstructure which is

impossible for traditional casting and forging.

– Alloy powder composition was developed based on traditional manufacturing,

specialized alloy composition could benefit AM processing.

– Heat treatment processes were not optimized for AM parts, fine AM

microstructures need to be treated differently.

40


Partnership with OSU

▪ AM test parts can be tailored to understand structure-property

relationships

▪ Microscopy

– MicroCT

– Advanced electron microscopy techniques

▪ DNV GL

– FEA analyses

– Lab mechanical testing

– Correlation to microstructure

41


CHALLENGE

SOLUTION VALUE

BENEFITS

Contact: Region: JIP I.D.:

JIP

Sour Service Performance of Additive Manufactured UNS N07718

42

Additive Manufacturing (AM) presents new opportunities and potential pitfalls to the Oil and Gas Market. Currently, additive manufacturing is not a production route addressed by NACE MR0175 / ISO 15156-2015.

Determining appropriate production techniques and screening methods to identify specific processes, batches or parts that resist environmentally assisted cracking (EAC) in sour service is critical to the

future of AM in Oil and Gas Exploration and Production Environments. Understanding the risks associated the incorporation of AM will be vital to determine the qualification processes needed for success.

(1) Identify and work with stakeholders to evaluate issues.

(2) Obtain components and characterize chemistry, microstructure and

mechanical properties.

(3) Sour service testing in DNV GL’s world-class H2S materials testing facility

(4) Analyze correlations and iterate production/testing to refine process and

understand how AM parts differ from conventional manufacture

Benefits to market will include:

AM sour-service performance from multiple vendors, correlation of

process variables, NDT and microstructure with sour performance,

informed risk-assessment regarding use of AM in oil and gas industry

Knowledge base of build-process/chemistry-

microstructure/mechanical performance

characteristics

Sour service evaluation and comparison to

wrought and welds

Process refinement to improve performance

[email protected] / 614 787 8995

[email protected] / 614 734 6121

North America 2017-XXX

Example Benefits of AM:

Reduce Development Time / Downtime

Enable new technologies

Manufacture and repair on-demand and on-location

(e.g. platforms)

Manufacture complex shapes without

machining facilities

mailto:[email protected]:[email protected]


The AM Performance Pipeline

Build Processing Microstructure Performance

43


Ex: Oil and Gas for Sour Service and Seawater CP environments

NACE MR0175

Material/Composition

Production Process

For AM, knowledge-base needs to be generated for the AM performance pipeline

44

Seawater CP

Material/Composition

Production Process

Microstructure influences performance, H embrittlement, etc.


AM Process Variables

AM

• Orientation

• Build parameters

• Microstructural Features

• Porosity

• …

Vs. Conventional Forging

45


AM and OG Stakeholders

AM

OG Asset Owners

Operators

OEMs

AM Vendors

Powder Manufacturers

3rd Parties, Regulators,

SMEs

46


Seifi’s Path towards Qualification

Barr

iers • Presence of

Defects

• Anisotropy

• Surface Roughness

• Similitude between coupons and actual parts

ND

T • X-ray CT• Ultrasonic

testing

• Eddy current

• Optical examination

Develo

pm

ent Path • AM standards

across production chain

• Fracture/fatigue testing

• NDT capability, e.g.watermarking

• In situ process monitoring

• Microstructure/ Residual Stress/

47

Seifi, et al. 2017: "Progress Towards Metal Additive

Manufacturing Standardization to Support Qualification and

Certification," JOM, 69, 439-455 (2017)


Prior Experience with AM Microstructures and Performance

Idell 2016

Continuous melt/resolidification process

Microsegregation

Delta-phase microplatelets

Voids + high strain fields

Novel HT required

Keller 2017

Models: Finite Element, Phase Field, CALPHAD

Microstructure Prediction

Validate against in-process, post-build and XRD

Kovacs 2016-2017

17-4 PH: Chemical, Mechanical, Microstructure,

Electrochemistry

AM more prone to corrosion, failed NACE Method A (SSC)

< 24 hours

Iterating on HT and tests led to acceptable performance,

~wrought

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Idell, et al. 2016: JOM 68:950-959 (2016)Keller, et al. 2017: Acta Materialia. 149, 244-253 (2017)

Kovacs, et al. 2017: NACE Corrosion 2017, New Orleans, LA: Paper No. 9667.Kovacs, et al. 2018: NACE Corrosion 2018, Phoenix, AZ: Paper No. 11212.


JIP Structure

Identify and Assemble Stakeholders

Identify Materials and Environments of Interest

Identify Microstructure/Performance

Test Matrix

Iterate on Production, Processing and Testing

Encapsulate Knowledge Base, Next Steps (=> Qualification Cmte)

49


Proposed JIP Flow

50

Phase 0 – Select Materials – Wrought/AM 1/ AM 2

Note: AM material to be donated by participants

Phase 1 – Microstructural Characterization

• Advanced SEM

• Grains size/dist/ppt/GB characterization

• TEM if needed

Phase 2 – Mechanicals Per API 6A CRA

• Tensiles/Charpy/CTODs

Phase 3 – Environmental Testing


Proposed JIP Flow

51

Phase 3 – Environmental Testing

Sour Service Testing

Preliminary Testing – 4 point bends (Level V)

• Wrought/AM1/AM2

• Multiple Orientations

• Based on results perform limited SSR Testing

• 6 SSR in Environment

Seawater + CP Testing

FCGR/SCGR testing on AM1/AM2 to compare

with wrought data

• Wrought data donated by DNV GL

• Post Test Characterization to understand

crack morphology and interaction with

microstructure


Flow and Details

▪ Summer 2018: Finalize memberships

▪ Fall 2018

– Phase 0 Stakeholders donate components for testing

– Phase 1 Microstructure characterization

– Phase 2 Mechanical evaluation

– Decision point #1

▪ Spring 2019

– Phase 3a/b: First-wave of exposure testing (seawater CP or sour)

– Microscopy and evaluation

– Decision point #2 (3a/3b may be in parallel)

▪ Fall 2019

– Sour service testing

– -Four point bend testing in various orientations

– SSR of select

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Membership Fee:

• 30k + Donated AM materials

Members/Invites:

• Arconic

• Baker Hughes GE

• Chevron

• Carpenter

• Dresser-Rand/Siemens

• GE Additive tentative

• Matheson tentative

• Technip/FMC


SAFER, SMARTER, GREENER

www.dnvgl.com

The trademarks DNV GL®, DNV®, the Horizon Graphic and Det Norske Veritas®

are the properties of companies in the Det Norske Veritas group. All rights reserved.

53

Liu Cao Chris Taylor

[email protected] [email protected]

614-761-6993 614-787-8995
mailto:[email protected]

testing of additive manufactured corrosion- resistant alloys ... - dnv gl am materials...nace tm0177...

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